1954 – Best known in the genre for The Immortal Storm, a history of the science fiction fan movement from its beginnings up to World War II, which appeared first as a series in the pages of Fantasy Commentator.

1963-1966 – Other works for which Sam is noted include Explorers of the Infinite and Seekers of Tomorrow, both collections of author profiles which appeared in various SF magazines.

1970 – Sam was consulting editor for The Pulps, an anthology of pulp magazine fiction, and general editor of the two important Hyperion Press Science Fiction Classics reprint series.

1972 – A member of the Science Fiction Hall of Fame.

1980 – Science Fiction by Gaslight; The Man Who Called Himself Poe; Under the Moons of Mars; Strange Horizons, another collection of author profiles; Science Fiction in Old San Francisco; and A. Merritt: Reflections in a Moon Pool.

1981 – He was the recipient of the Pilgrim award from the Science Fiction Research Association.